PHP Codeigniter：将动态表单数据传递到视图，而无需在验证错误时从数据库重新获取

Question

I am making a basic signup page using PHP Codeigniter.

On the signup page, I ask the user to select from a selection of categories (via a <select> html element). These categories are stored in a list in my MySQL Database.

My current method is to fetch this list from the DB when the user calls the function to load the page and then display it to them. However, if the user enter's incorrect data and the page must be reloaded with the validation errors, the variable that holds the data in the list seems to be cleared, and I must refetch the list data from the database before redisplaying the page.

I believe there's something in the documentation about how to set this variable to be permanently available but upon looking again, I had no luck in finding it.

Could anyone possibly point me in the right direction? It seems silly to me to have to need to refetch this data every time (I know that people won't be putting in wrong info often, but this will come in handy in a few situations).

NOTE: This is not an issue regarding remembering user selections.

Answer 1

You just need to set it as the default value, for example

<input type="text" name="username" value="<?php isset($_POST['username']) echo $username;?>" />

That way, $_POST['username'] will always be available.

Answer 2

this example is for a select drop down list using ci form helper (i'm modifying this from another form so hopefully its all correct)

the Array of select values is: $categoryarray
the drop down field name is 'category'
the default value is $defaultcategory
a css class to style (bootstrap etc): $dropclass = 'class="input-medium"';

the line of code is:

  form_dropdown('category',$categoryarray,set_value('category',$defaultcategory),$dropclass).form_error('category');

the form_error('category'); at the end is for showing a validation error message and even though there is a default value - if the form fails validation from another field in the form - this will 'remember' what the user selected.

EDIT !

ok there is good and bad news. bad news - if the categories are coming from a database then you need to get them again. good news - CI remembers what category the user selected from the drop down list.

and the bad news actually isn't that big a deal - if you create the category array in your model. then its just one line of code to add to the validation.

// In the Model 

    function makedropdown() {

// get your category list 
$cats = $this->getAllCategories() ;

$categoryarray = array();

   // make the array 
 foreach ( $cats->result() as $row ) {

 $categoryarray[$row->category] =  $row->category ; }

return $categoryarray ;

}

someone has filled out the form, we run validation, validation fails. in the controller:

if ( $this->form_validation->run($formrules) == FALSE ) {

// get the categoryarray
$data['categoryarray'] = $this->categorymodel->makedropdown() ; 

// load form again
$this->load->view( 'myform', $data ); }

So even though we are getting the categories again from the db to dynamically populate the select list - CI still remembers the users choice from the first time they did the form.

And what about a default category for the drop down? if its not going to change then it can be set as a config. if the category values are coming from a database and they can change - then the default category could be created in the model.

EDIT 2

gosh i always do this anyway so why didnt i think of it for this. so yeah this is yet another reason to make a specific method for showing your view

 function _showCategoryForm(){

 // get the categoryarray
$data['categoryarray'] = $this->categorymodel->makedropdown() ; 

// anything else thats needed for the view 

// load form view
$this->load->view( 'myform', $data ); }

NOW we dont have any repeated code, and its easy to customize the validation failure with an error message if needed.

// since i'm grinding on this - the validation should happen in a model 
// and that method returns true or false
if ( $this->somemodel->validateCategoryForm() == FALSE ) {

// custom obnoxious error message 
$this->formerrormessage = "What part of required is eluding you?" ;

$this->_showCategoryForm() ;  }

This is much better because if the needs of your form changes - the change is only in one place. Also i added an underscore to remind us all that private methods are a good practice. And the form validation should be separate in a model, that is called by the controller.